Title (en)

RADIO FREQUENCY QUADRATURE COIL CONSTRUCTION FOR MAGNETIC RESONANCE IMAGING (MRI) APPARATUS

Publication

EP 0459569 A3 19920610 (EN)

Application

EP 91201229 A 19910523

Priority

US 53012790 A 19900529

Abstract (en)

[origin: EP0459569A2] A first circular ring of a given inductance is coupled to second and third circular rings by a plurality of equally spaced parallel rods to form a birdcage coil. The second and third rings have a combined inductance the same as that of the first ring and are located adjacent to each other at an end of the rods opposite the first ring. A tune-detune circuit is located at the end of and couples each of the rods to the second and third rings. This circuit includes parallel capacitances whose combined value is the same as the capacitance coupling the rods to the first ring to selectively tune the coil to a given radio-frequency. PIN diodes selectively rf couple the parallel capacitances respectively to the second and third rings. Direct current diode bias voltages are applied to the second and third rings which act as busses for the bias voltages. The second and third rings are split in half and capacitively coupled to permit applying relatively higher (DC) bias voltages to the diodes. The coil is divided into upper and lower halves with open space between the rods of the upper half to permit access to a patient's head and for patient comfort during examination. <IMAGE>

IPC 1-7

G01R 33/32

IPC 8 full level

A61B 5/055 (2006.01); G01R 33/34 (2006.01); G01R 33/36 (2006.01)

CPC (source: EP US)

G01R 33/34046 (2013.01 - EP US); G01R 33/3657 (2013.01 - EP US)

Citation (search report)

• [A] EP 0170558 A1 19860205 - THOMSON CGR [FR]
• [A] EP 0315382 A2 19890510 - UNIV CALIFORNIA [US]
• [A] EP 0346049 A2 19891213 - GEN ELECTRIC [US]
• [A] EP 0171972 A2 19860219 - PICKER INT INC [US]
• [A] MAGNETIC RESONANCE IN MEDICINE vol. 13, no. 3, March 1990, pages 385-397, Duluth, US; H. REQUARDT et al.: "Switched Array Coils"
• [A] JOURNAL OF MAGNETIC RESONANCE vol. 86, no. 3, February 1990, pages 645-651, Duluth, US; K. DERBY et al.: "Design and Evaluation of a Novel Dual-Tuned Resonator for Spectroscopic Imaging"
• [AP] JOURNAL OF MAGNETIC RESONANCE vol. 91, no. 3, February 1991, pages 527-538, Duluth, US; P.M. JOSEPH et al.: "A Novel Rotating-Field Coil for Sodium Imaging"

Designated contracting state (EPC)

DE FR GB NL

DOCDB simple family (publication)

EP 0459569 A2 19911204; EP 0459569 A3 19920610; EP 0459569 B1 19970319; DE 69125209 D1 19970424; DE 69125209 T2 19970828; JP 3164376 B2 20010508; JP H04231028 A 19920819; US 5075624 A 19911224

DOCDB simple family (application)

EP 91201229 A 19910523; DE 69125209 T 19910523; JP 12396791 A 19910528; US 53012790 A 19900529